8 Rivers, the Allam Cycle, and what it all means

In a world full of apparently groundbreaking new technologies being announced on a seemingly daily basis, why take the 8 Rivers project seriously?

Put simply: because global-scale investors looking for low-carbon energy production in a post-oil, post-nuclear energy era are backing it and its successful implementation would reduce total carbon emissions from electricity and urea production – both essential inputs to the New Zealand economy for the foreseeable future.

The Allam Cycle, the core of the 8 Rivers technology, achieves something not seen before. It uses so-called ‘super-critical’ carbon dioxide to propel the turbines in a gas-fired electricity generation plant, making it highly energy efficient.

This means that it “captures all of the carbon dioxide it produces without significantly higher costs, in part by relying on the greenhouse gas itself to crank the turbine that generates electricity,” said American publication Technology Review last August.

“The technology could enable a new generation of plants that provide clean power, without the development risks of nuclear, the geographic restrictions of hydroelectric, or the intermittency issues of solar and wind.”

That was three months after NET Power, a Durham, North Carolina-based company, opened a US$400m ($587m) 50 Megawatt demonstration plant using the Allam Cycle technology – named after its inventor, UK academic Rodney Allam.

Earlier this month and three months of testing further on, NET Power was able to announce an investment of undisclosed size from three major global energy and infrastructure firms to develop the technology further.

The first phase of testing at the North Carolina plant had “successfully demonstrated the novel combustor at full scale and the operability of the NET Power process. The last phase of testing

. . . is expected to completed by early 2019.”

Fortune 500 company Occidental Petroleum’s Oxy Low Carbon Ventures unit, and nuclear power producer Exelon – both looking for low-carbon options as their current business models disappear – have invested accordingly.

Japanese industrial giant Toshiba wants to manufacture the turbines and multinational US firm McDermott is lining up for plant construction.

In New Zealand, 8 Rivers is touting a three-block approach to the project:

• Block One – a zero-emissions Allam Cycle 175MSW power generation plant using natural gas.

It would power the hydrogen plant, but also provide power to the grid and could act like a faststarting peaker plant for times when renewables can’t meet total electricity demand.

That could help the Government achieve zero-carbon electricity production by 2035 – a goal that will not be reached while maintaining secure supply unless there is still some gas-fired electricity generation in the system.

The 8 Rivers plant could hasten the closure of the Genesis Energy coal-fired power station still running at Huntly and displace other, less carbon-efficient gasfired plants.

Waste CO2 would be available for other industrial processes or pumped back into depleted oil and gas fields, potentially improving recovery of hydrocarbons as those fields decline;

• Block Two – a hydrogen production system developed by 8 Rivers for integration with the Allam Cycle, which synthesises hydrogen and CO2 feedstocks, capable of producing zero-emissions hydrogen at much lower cost than pure ‘green’ hydrogen created from renewable sources.

• Block Three – urea production.

New Zealand uses around

900,000 tonnes of urea annually,

600,000 tonnes of which is imported. The 8 Rivers plant could produce around 2 million tonnes of urea annually, meeting all of New Zealand’s demand and leaving 1.1 million tonnes for a new export industry that would displace higheremission urea produced elsewhere.